1. Field of the Invention
The present invention relates to the field of fly ash disposal. Specifically, this invention relates to a method for removing the toxicity within fly ash prior to disposal or in the alternative recycling the processed fly ash into a useable product.
2. Description of the Prior Art
The following published patent applications are the closest prior art known to the inventor:    1. Title: A fly ash disposal method    Patent Publication No: CN102772978A    Applicants: Jun Xu, Wei Zeng    Inventor: Jun Xu    Filing Date:: 2012-7-6    Date of Publication: 2012-11-14    Abstract: This invention reveals a disposal method of fly ash, as shown in the following steps: Collect fly ash from the incinerator flues of waste incineration power plants; place the fly ash in an air-free pressure-tight vacuum heating device or in a pressure-tight device with protective atmosphere for fully heating; transport the exhaust gas generated during the heating based on the prior step into a power plant boiler through pipe. The disposal method in this invention is able to dramatically lower the dioxins level in the fly ash, which will greatly reduce the damage of dioxins to the environment and human body.    2. Title: A new fly ash disposal method    Patent Publication No: CN101569890    Applicant: Beijing Xinbeishui Cement Co., Ltd.    Inventors: Yungui Xiong, Ji Zhang, Jinshan Cai    Filing Date:: 2009-5-25 Date of Publication: 2009-11-4    Abstract: This invention refers to a new fly ash disposal method, as shown in the following steps: After a road tanker enters into a factory, the vacuum pressure carried along with the road tanker it will punch fly ash into ash storage bin. A metering device controls the amount of fly ash fed into the storage bin. Then fly ash is moved into a pneumatic conveyance bin. Then the fly ash in the conveyance bin is pneumatically Then the fly ash is pneumatically transported to burner or spray gun device at kiln hood, and injected into rotary kiln through burner or spray gun device for incineration. Heavy metals in fly ash will be solidified into cement and will not be precipitated out. Fly ash contains acute toxic and hazardous dioxins that can be completely decomposed into water, carbon dioxide and other substances in a kiln under high temperature. The advantages of this invention are: Ejection point is set in kiln and can effectively solve the problem of harmless treatment of acute toxic and hazardous dioxins in fly ash; heavy metals in fly ash are solidified by cement and will not be precipitated out; at last, these heavy metals enter into cement products, i.e., waste is turned into resource, without secondary pollution; its process is novel, unique, simple and practical; the process is continuous, automatic, safe and reliable.    3. Title: Method of collecting dioxins in flue gas from household waste incineration    Patent Publication No: CN102000443A    Applicant: Tianjin University    Inventors: Hongting Ma, Jinglong Sun, Guoli Yang, Fangchao Wang, Sufeng Hao, Minghui    Wang, Dan Du.    Filing Date:: 2010-11-5 Date of Publication: 2011-4-6    Abstract: This invention reveals a method of collecting dioxins in flue gas from household waste incineration, as shown in the following steps: Enable the flue gas produced by household waste incineration to pass through the first level casing heat exchanger cartridge, and through at least a first-level post-processing casing heat exchanger in sequence; the flue gas that has flowed out of the last level treatment casing heat exchanger sequentially passes through a hexane gas washing bottle, a buffer bottle, a glass fill tube, a toluene gas washing bottle and a buffer bottle placed in ice water mixture; using a toluene solution of a gas washing bottle for cleaning the inner wall of the heat exchange casing of the first level casing heat exchanger and collect toluene solution after washing; set a collection bottle at the bottom of the first level post-treatment casing heat exchanger to receive the condensation water of substances containing dioxins due to condensation of flue gas, and take cartridge, condensation water, resin, and toluene used to clear the inner wall of the first level casing heat exchanger as final samples. This method enhances the enrichment efficiency of dioxins, so as to monitor dioxins in the household waste incineration tail gas in a more accurate way.    4. Title: A harmless treatment method and device for waste incinerator fly ash    Patent Publication No: CN101462835    Applicants: Shanghai Solid Waste Disposal Center; Shanghai University; Shanghai Chengtou Environment Industry Development Company Limited    Inventors: Qifang Wu, Guangren Qian, Min Pu, Luquan Zhou, Zhengfei Tang, Xisheng Wang    Filing Date:: 2008-9-1 Date of Publication: 2009-6-24    Abstract: This invention reveals a harmless treatment method of waste incineration of fly ash and involves: Prewetting; slurrying—mixing of fly ash and water in the ratio of 1:2 to 1:20 and stirring the mixture for making mortar; rinsing and settling fly ash to dissolve soluble salt in it; agent modification; concentration—enabling mortar's moisture content to drop to 70% to 90%; dehydration—enabling mortar's moisture content to drop to a value below 35%; water treatment—charging CO2 or acid to enable strong alkaline supernatant (pH value up to 11-12) to change into neutral water (pH value 6.0-8.5); add flocculant to capture micro particles and speed up the precipitation process; preparing cement—Add finished products of fly ash into cement rotary kiln and heat them to 1,000 C to 1,450 C, so that they can be decomposed into dioxins and suppress their generation under low temperature; enhance boiling points of heavy metals and passivate volatilization performance.    5. Title: A cooperative and pretreatment method with cement kiln for household waste incinerator fly ash of backflow leachate    Patent Publication No: CN101773924A    Applicants: Tsinghua University Inventor: Yiying Jin, Junli Zhang, Yongsheng Ling, Huan Li, Lei Wang, Yongfeng Nie    Filing Date:: 2010-1-29 Date of Publication: 2010-7-14    Abstract: This invention reveals a cooperative and pretreatment method with cement kiln for household waste incinerator fly ash of backflow leachate in solid waste treatment and disposal technology fields. The method comprises four stages, respectively rinsing and dechlorination of fly ash, washing water treatment, dehydration of ash by rinsing and in-kiln calcination. Remove chlorine of fly ash by rinsing, chelate and make coagulative sedimentation for heavy metals rinsed out, and allow them to enter into kiln with water-washed fly ash after filter pressing. Neutralize the eluate and allow heavy metals to settle, so as to ensure that washing water can meet discharging standards. Using the invention for fly ash disposal can not only save industrial raw materials of cement, but also effectively cure heavy metals, thoroughly burn dioxins, safely, economically and conveniently dispose of fly ash, and greatly enhance environmental benefit, economic benefit and social benefit. This invention saves land, water and investment and works stably, so as to ensure stable effects of processing water-washed fly ash and eluate; this will not produce secondary pollution.    6. Title: A method of preparing lightweight concrete by using household waste incinerator fly ash    Patent Publication No: CNO1531492    Applicant: Shanghai Institute of Technology    Inventors: Haiying Zhang, Youcai Zhao, Jingyu Qi, Shi Xu    Filing Date:: 2009-4-17 Date of Publication: 2009-9-16    Abstract: This invention reveals a method of preparing lightweight concrete with household waste incinerator fly ash. Matching ratios of materials of various components of the lightweight concrete are as follows: Waste incinerator fly ash 330-370 kg/m3; 525# common silicate cement 450-475 kg/m3; water-granulated slag 325-340 kg/m3; common clay ceramsite 350-370 kg/m3; crushed diabase 230-240 kg/m3; additive 2.7-2.9 kg/m3. This invention helps people to use household waste incinerator fly ash for preparing lightweight concrete and to solidify heavy metals in fly ash, thus achieving the objective of harmless treatment of household waste incinerator fly ash. This invention process is simple and the obtained finished concrete products have the grade strength of CL40, have the apparent density of 1,800 and have good macroscopic performance.    7. Title: A method of preparing ecological concrete by using incinerator fly ash as additive    Patent Publication No: CN1541968    Applicants: Tongji University Inventors: Huisheng Shi, Ling Yuan    Filing Date: 2013 Nov. 6 Date of Publication: 2004-11-3    Abstract: This invention refers to a method of preparing ecological concrete by using incinerator fly ash as additive. The method takes cement, active slag fines and incinerator fly ash as cementing materials, together with auxiliary materials (zeolite and additives like sodium silicate and water reducing agent), to prepare ecological concrete according to their proper matching ratios. With good mechanical property and excellent permeability resistance performance, the concrete can effectively absorb, take and stabilize heavy metals and other hazardous substances to enable them to be difficult for leaching-out and conform to safety use standards. This invention will recycle incinerator fly ash for use again, and produce apparent social benefits and economic benefits.    8. Title: A method of stabilizing and recycling municipal solid waste incinerator fly ash    Patent Publication No: CN 01050076    Applicant: She Zhang    Inventors: She Zhang, Huiwen Ma, Libing Sun    Filing Date:: 2007-5-17 Date of Publication: 2007-10-10    Abstract: This invention refers to a method of stabilizing and recycling municipal solid waste incinerator fly ash. The method replaces fine aggregates (5% to 25% of concrete or mortar) with municipal solid waste incinerator fly ash to prepare concrete block or masonry mortar. By using the method of stabilizing heavy metal elements of fly ash with hydration-ammonium bicarbonate acidification-ammonium sulfide vulcanization, stabilize heavy metal elements of fly ash under the water-insoluble state without additionally introducing any metal ions. After stabilizing treatment, the fly ash can be used to replace fine aggregates of concrete or mortar. This will not produce any adverse effect upon physical property of concrete and mortar. In addition, fly ash has the hydraulicity function, so it can enhance physical strength of concrete. Once concrete or mortar breaks into pieces, their leachate's heavy metal dissolution concentration is far less than the threshold values specified in the Identification Standards for Hazardous Wastes for Identification for Extraction Toxicity (GB5085.3-1996).
The summarized patents and published patent applications which are all published patent applications in Mainland China are entirely in Mandarin. The above English translations were received through a representative of the present inventors and/or a company in mainland China to which the respective corresponding patent applications resulting in the above identified published patent applications were assigned.
There are some reports about using fly ash for producing and making concrete block and solidifying heavy metal, but there is no report or previous patent or previous patent application that discloses the method described herein.